Apparatus for forming paper between two forming wires



July 26, 1966 L. EMBRY 3,262,841

APPARATUS FOR FORMING PAPER BETWEEN TWO FORMING WIRES Filed April 29,1963 2 Sheets-Sheet l [N VENTOR. LAMAR E MB R Y M: .W W

B Y ATTORNEYS July 26, 1966 L. EMBRY 3,262,841

APPARATUS FOR FORMING PAPER BETWEEN TWO FORMING WIRES Filed April 29,1963 2 Sheets-Sheet 2 INVENTOR.

LAMAR EMBRY ATTORNEYS United States Patent 3,262,841 APPARATUS FORFORMING PAPER BETWEEN TWO FORMING WIRES Lamar Embry, Kawerau, Bay ofPlenty, Auckland, New Zealand, assignor to Beloit Corporation, Belolt,W1s., a corporation of Wisconsin Filed Apr. 29, 1963, Ser. No. 276,615 4Claims. (Cl. 162-'301) This application is a continuation-in-part of mycopending United States application Serial No. 855,392, filed November25, 1959, and now abandoned.

The present invention relates in general to paper making equipment, andparticularly to highspeed paper making machines having improved meansfor removing fluids from watery pulp stock or the like.

As is well known in the paper making art, a large portion of the waterin the pulp stock deposited on the endless Fourdrinier wire or fabricweb must be removed before the wire reaches the couch roll at the end ofthe forming zone. Heretofore, the conventional types of Fourdrinierpaper machines for manufacturing paper, tissue, box-board and the likehave been arranged so that the pulp stock of fiber, water, additives andthe like flow from a headbox onto a traveling endless Fourdrinier wiresupported by a series of table rolls extending transversely of the axisof travel of the wire and spaced from each other, so that the liquid inthe stock can immediately drain therefrom through the forming wire,between the table rolls and into a drip pan positioned below the tablerolls. Additional liquids remaining in the stock are subsequentlyremoved by suction boxes over which the Wire travels, and a suctioncouch roll is usually provided for removing still more of the liquidfrom the stock.

However, in a typical high-speed Fourdrinier machine wherein the machineis operated at high speeds, that is, up to and exceeding 2500 feet perminute, the vacuum created by the table rolls has a tendency to removewater at an undesirably high rate, thus adversely affecting theformation of the sheet on the wire and making it diflicult to obtain thedesired character of paper formation. The heavy drag produced by thevacuum boxes over which the wire is drawn at high speed imparts a highload on the forming wire and produces substantial abrasive frictionbetween the wire and the vacuum boxes, requiring a large input of powerfor driving the wire and greatly shortening its life. Additionally, suchan arrangement produces a two sided paper sheet wherein the oppositesides are of different quality, since downward removal of water causesthe fine fibers to be washed from the lowermost side of the sheet as itpasses through the forming zone.

Accordingly, an important object of the present invention is to providea method and apparatus for producing paper or the like at high speed andwhich are relatively simple and elfectively obviate the aforementioneddisadvantages.

Another object of the present invention is the provision of a high speedFourdrinier type of paper machine wherein effective drainage of Waterfrom the pulp stock deposited on the Fourdrinier wire is achievedWithout the use of suction boxes, and particularly to provide such apaper machine wherein the liquids are removed from both sides of thepulp stock so that both sides of the sheet have a surface ofsubstantially identical quality.

A further object of this invention is to provide a high speed papermachine of the aforesaid type which removes the liquids from the pulpstock at a rate substantially above that heretofore known, and furtherto provide such a machine which is much less expensive and complex, aswell as considerably shorter in length as compared to the conventionalFourdrinier machines.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

In the drawings:

FIG. 1 is a diagrammatic illustration of a high speed paper machine inaccordance with the invention;

FIGS. 2 through 4 are schematic illustrations at successive stages inthe formation of the paper sheet;

FIG. 5 is a schematic illustration of the forming wires passing over aturning roll;

FIG. 6 is a view similar to FIG. 5 showing the forming wires beingturned in the opposite direction through a larger angle; and

FIG. 7 is a view similar to FIGS. 2 through 4 illustrating the sheet asit leaves the paper machine.

Referring to the drawings wherein a preferred embodiment is illustrated,FIG. 1 shows a bottom endless forming wire 10 onto which the pulp stockof fiber, water, and the usual additives is to be deposited from aconventional headbox 11. The bottom wire 10 has a first substantiallyhorizontal initial run 12 which extends from the breast roll 13 disposedimmediately below the headbox 11, over a forming board 14 of usualconstruction and a plurality of supporting rolls 15, to a first of theseries of deflector rolls 1'6, 17 and 18.

The forming wire 10 proceeds through a series of progressively steeperdownwardly inclined runs 19 and 20 guided by the deflector rolls 16, 17and 18, respectively, and deflector strips 21 and 22 disposedtherebetween. The wire 10 then passes through a downwardly directedvertical run 23 between the deflector 18 and a turning roll 24, and adownwardly offset horizontal run 25 between the turning roll 24- (FIG.6) and a suction couch roll 26. The wire 10 is then diverted downwardlyalong a downwardly sloping run 27 between the couch roll 26 and a guideroll 28, and returns to the breast roll 13 along a downwardly inclinedreturn run 29 extending between the turning roll 28 and return roll 30,a run 31 between the return roll and return roll 32 wherein the wire 10is tensioned by the stretcher roll 33, and a long upwardly inclinedreturn run 34 between the guide roll 32 and the breast roll 16.

Coacting with the bottom wire 10 is an upper forming Wire 35 which has avery shallow inclined initial run 36 between the roll 37 and the firstdeflector roll 16 so that the wires 10 and 35 are gradually movedtogether until they are spaced apart a predetermined distance to form asandwiched layer with the stock. The top wire 35 is deflected with thewire 10 around the deflector rolls 16, 17 and 18, and the turning roll24. Thus the progressively steeper inclined runs 39 and 40 overlie theruns 19 and 20 of the bottom wire 10, and the vertical and horizontalruns 41 and 42 conform, respectively, to the runs 23 and 25 of thebottom wire 10. The turning roll 43, the return rolls 44 and 45, and thestretcher roll 46 guide the upper wire 35 to the breast roll 37 along arising vertical run 47, an upwardly inclined return run 48, a stretcherrun 49, and a downwardly inclined return run 50, respectively.

In one practical example of the present invention, the forming wires 19and 35 are driven at 1500 feet per minute or higher and may have meshsizes of 6852 wires per linear inch for newsprint and 54-36 wires perlinear inch for liner board. In this example, the supporting rolls 15are preferably of dandy type construction to prevent suction on thedownstream side thereof, and may be fourteen-inch diameter rolls. Itwill be appreciated that if the supporting rolls 15 are solid rolls,they will create enough vacuum at very high speeds to vaporize the waterand to pull pulp fibers through the bottom wire 10. The deflector rolls16, 17 and 18 may be approximately twentyfour inch dandy type rolls, andmay be equally spaced approximately thirty-five inches between rollcenters and positioned to dispose the substantially planar downwardlysloping runs 19 and 20 at 30 and 60, respectively, to the horizontal.

The spacing and diameter of the deflector rolls 16, 17 and 18 is notcritical, but the rolls must be of sufficient strength to minimize rolldeflection with wire tension of about fifteen pounds per linear inch. Itshould be apparent that one large diameter roll could replace thedeflector rolls 16, 17 and 18 without departing from the scope of theinvention. In this example, the approximate distance from the center ofthe breast roll 13 to the first deflector roll 16 may be about ten feet,and the turning rolls 24 and 38 may be approximately 34-inch diameterdandy type rolls, and the couch roll 26 should be of the suction type.

As will be apparent, a drip pan 51 underlies the forming wire over amajor portion of the run 12, the entire runs 19, and 23 and a majorportion of the downwardly offset run 25, and a drip pan 52 is disposedto receive water expelled from the sheet by centrifugal force producedat the declining runs 19 and 20. A vacuum pick-up roll 53 engages thesheet at an intermediate point along the run 27 to pick up the sheet andtransfer it to the usual press section.

In the operation of the invention, the watery pulp stock flows bygravity or pressure from the headbox 11 onto the bottom forming wire 10at the right end of the initial run 12 thereof in the region of theforming board 14 so that a uniform layer of stock covers this wire. Thecovering wire 35 converges gradually onto the layer of stock on thebottom wire 10 so that part of the water and other liquid is expressedfrom the pulp by the squeezing action of initial runs 36 and 12. As thissandwiched layer progresses toward the deflector roll 16, these liquidsare thus forced through both the top and bottom forming wires, and thewater which is forced upwardly through the top wire 35 remains thereonuntil the wires reach the first deflector roll 16.

FIGS. 2, 3 and 4 illustrate three successive steps of this squeezingaction, with FIG. 2 showing the sandwiched layer of wires and stockapproximately above the righthand support roll 15 (FIG. 1), before anysubstantial amount of water is removed therefrom. FIG. 3, on the otherhand, illustrates an intermediate step, approximately above theleft-hand support roll 15 (FIG. 1) where the stock fibers are closersince the squeezing action has removed a substantial volume of liquid,and FIG. 4 illustrates the pulp stock prior to the turn around the roll16.

As the sandwiched layer passes around the deflector rolls 16, 17 and 18at high speed, the water in the pulp stock is subjected to centrifugalforce suflicient to remove a substantial portion of the water from thestock, and throw it into the pan 52. As shown in FIGS. 1 and 5, therolls 16, 17 and 18 turn the sandwiched layer through a right angle sothat each roll effects a thirty degree turn. Also the water which wasexpressed by the squeezing action of the wires over the runs 12 and 36and remained on and followed the top wire 35 is thrown by centrifugalforce into the pan 52 at this stage. It will be noted that over thecourse of the turn identified by the runs 19 and 20, the water is beingdravm by centrifugal force through the top wire 35.

The wires 10 and 35 then make a turn in the opposite direction about theturning roll 24 (FIG. 6) wherein water is thrown by centrifugal forcethrough the bottom wire 10 into the pan 51. The centrifugal force whichis imparted to the water in the stock is proportional to the square ofthe angular velocity of this water, and since this angular velocity isdetermined by the speed of the wires 10 and 35, the latter speed becomesan important consideration in the proper operation of the invention.

However, the amount of water to be removed, the particular type of stockbeing used, and the diameter of the rolls 16, 17, 18 and 24 are alsofactors which must be considered in determining the speed of the wires.As a practical matter, the minimum speeds at which the invention willfunction properly appear to be approximately 1500 feet per minute forlight weight paper, with higher speed being more desirable.

Conventional drive means or motors D D (indicated diagrammatically)drive the wires and 10, respectively; the drive D turning the couch 26and turning roll 28 to drive the wire 10 in conventional manner and thedrive D turns corresponding rolls 24 and 38 to drive the wire 35.

The newly formed sheet S (FIG. 7) is then carried between the wires 10and 35 along the runs 25 and 42, and over the suction couch roll 26which pulls the sheet from the top wire 35 and causes it to adhere tothe bottom wire 10 along the downwardly sloping run 27. The sheet isthen picked up by the vacuum roll 53 which is disposed above the turningroll 28, and then carried to a press section (not shown) or the like foradditional processing in the conventional manner well known to the papermaking art.

It will be apparent that by employing the use of centrifugal force inthe regions of the deflector rolls 16, 17 and 18 and the turning roll 24to expel water from both sides of the sheet, the complete elimination ofvacuum producing table rolls becomes possible. This greatly increasesthe life of the forming wires 10 and 35 since abrasive friction betweenthe vacuum boxes and the wires, and between the table rolls and thewires is eliminated, and consequently there is a substantial reductionin power consumption due to the reduction in drag on the wires.

Additionally, improved formation of the sheet of paper is realized, asthe two-sidedness produced by the former methods is eliminated becauseof the even distribution of fine fibers adjacent the top and bottomsurfaces (FIG. 7) of the newly formed sheet S which is achieved bydrainage from both the top and bottom sides of the sheet. Also, aconsiderably shorter machine with correspondingly shorter wires may beused, as compared to the length of machinery required when a table rollsection and a suction box section are present, thus resulting in a muchcheaper installation.

While the method herein described, and the form of apparatus forcarrying this method into effect, constitute preferred embodiments ofthe invention, it is to be understood that the invention is not limitedto this precise method and form of apparatus, and that changes may bemade in either without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. Apparatus for forming a web of paper or the like, comprising a frame,a bottom forming wire, a plurality of guide rolls on said frame fordirecting said bottom forming wire through a substantially horizontalrun, headbox means for feeding watery pulp stock onto said bottomforming wire at the upstream end of said horizontal run, an upperforming wire substantially identical to said bottom forming wire, guiderolls for directing said upper forming wire through an initial runwherein it gradually converges into sandwiched relation with said bottomforming wire and stock to progressively express the liquids from thestock through each of said wires, first turning roll means for guidingthe sandwiched forming wires and stock through a first turning path inone direction, second turning roll means for guiding said sandwichedforming wires and stock through a second turning path in an oppositedirection, drive means for moving said wires at a predetermined speedsuflicient to discharge the liquids in the stock by centrifugal forcethrough one of said wires as said sandwiched wires and stock pass aroundsaid first turning roll and then through the other of said wires as saidsandwiched wires and stock pass around said second turning roll toremove substantially all of the liquids from the stock by centrifugalforce to produce a sheet of paper or the like, and means for separatingsaid forming wires and removing the newly formed sheet therefrom.

2. Apparatus for forming a web of paper or the like, comprising a frame,a bottom forming wire, a plurality of guide rolls on said frame fordirecting said bottom forming wire through a substantially horizontalrun, head'box means for feeding watery pulp stock onto the surface ofsaid bottom forming wire at the upstream end of said horizontal run, anupper forming wire substantially identical to said bottom forming wire,guide rolls for directing said upper forming wire through an initial runwherein it converges into sandwiched relation with said bottom formingwire, first turning means for guiding the sandwiched forming wires andstock through a first turning path in one direction, second turningmeans for guiding said sandwiched forming wires and stock through asecond turning path in an opposite direction, drive means for movingsaid wires at a predetermined speed sufficient to discharge the liquidsin the stock by centrifugal force through one of said wires as saidsandwiched wires and stock pass around said first turning roll and thenthrough the other of said wires as said sandwiched wires and stock passaround said second turning roll to remove substantially all of theliquids from the stock and produce a sheet of paper or the like, meansfor separating said superimposed forming wires and causing the newlyformed sheet to adhere to one of said forming wires, and pickup meansfor removing the newly formed sheet from said one wire.

3. Apparatus for forming a web of paper or the like, comprising a frame,a bottom forming wire, a plurality of guide rolls on said frame fordirecting said bottom forming wire through a substantially horizontalrun, headbox means for feeding watery pulp stock onto said bottomforming wire at the upstream end of said horizontal run, an upperforming wire substantially identical to said bottom forming wire, guiderolls on said frame for directing said upper forming wire through aninitial run wherein it converges into superimposed relation with saidbottom forming wire and stock, a plurality of deflector rolls on saidframe for guiding said superimposed forming wires and stock through afirst turning path including a series of succession of more steeplyinclined runs, second turning roll mean-s for guiding said superimposedforming wires and stock through a second turning path in an oppositedirection, drive means for moving said wires at a predetermined speedsufficient to discharge the liquids in the stock by centrifugal forcethrough one of said wires as said sandwiched wires and stock pass aroundsaid first turning roll and then through the other of said wires as saidsandwiched Wires and stock pass around said second turning roll toremove substantially all of the liquids from the stock and produce asheet of paper or the like, and means for separating said superimposedforming wires and removing the newly formed sheet therefrom.

4. Apparatus for forming a web of paper or the like, comprising a frame,a bottom forming wire, a plurality of guide rolls on said frame fordirecting said bottom forming wire through a substantially horizontalrun, headbox means for feeding watery pulp stock onto said bottomforming wire at the upstream end of said horizontal run, an upperforming wire substantially identical to said bottom forming wire, guiderolls for directing said upper forming Wire through an initial runwherein it converges into sandwiched relation with said bottom formingwire and stock, turning roll means on said frame for guiding thesandwiched forming wires and stock through turning path-s in oppositedirections, drive means for moving said wires at a predetermined speedsufficient to discharge the liquids in the stock by centrifugal forcethrough one of said wires as said sandwiched wires and stock passthrough a path in one turning direction and then through the other ofsaid wires as said sandwiched wires and stock pass through a path in anopposite turning direction to remove a substantial portion of theliquids from the stock and produce a sheet of paper or the like, andmeans for separating said wires and removing the newly formed sheet.

References Cited by the Examiner UNITED STATES PATENTS 1,544,904 7/1925Herb 162-348 1,722,503 7/ 1929 Millspaugh 162206 1,875,075 8/1932 Mason162-203 2,718,825 9/1955 Goodwillie 162-306 2,859,668 11/1958 Berlyn162213 FOREIGN PATENTS 3,583 9/1877 Great Britain. 4,182 8/ 1881 GreatBritain. 246,048 1/ 1926 Great Britain. 813,509 5/1959 Great Britain.

OTHER REFERENCES Perrys Chemical Engineers Handbook, 3d edition, 1950,McGraw-Hill Book Co., Inc. N.Y., page 992.

DONALL H. SYLVESTER, Primary Examiner. MORRIS O. WOLK, Examiner. S. L.BASHORE, Assistant Examiner.

1. APPARATUUS FOR FORMING A WEB OF PAPER OR THE LIKE, COMPRISING AFRAME, A BOTTOM FORMING WIRE, A PLURALITY OF GUIDE ROLLS ON SAID FRAMEFOR DIRECTING SAID BOTTOM FORMING WIRE THROUGH A SUBSTANTIALLYHORIZONTAL RUN, HEADBOX MEANS FOR FEEDING WATERY PULP STOCK ONTO SAIDBOTTOM FORMING WIRE AT THE UPSTREAM END OF SAID HORIZONTAL RUN, AN UPPERFORMING WIRE SUBSTANTIALLY IDENTICAL TO AID BOTTOM FORMING WIRE, GUIDEROLLS FOR DIRECTING SAID UPPER FORMING WIRE THROUGH AN INITAL RUNWHEREIN IT GRADUALLY CONVERGES INTO SANDWICHED RELATION WITH SAID BOTTOMFORMING WIRE AND STOCK TO PROGRESSIVELY EXPRESS THE LIQUIDS FROM THESTOCK THROUGH EACH OF SAID WIRES, FIRST TURNING ROOL MEANS FOR GUIDINGTHE SANDWICHED FORMING WIRES AND STOCK THROUGH A FIRST TURNING PATH INONE DIRECTION, SECOND TURNING ROLL MEANS FOR GUIDING SAID SANDWICHEDFORMING WIRES AND STOCK THROUGH A SECOND TURNING PATH IN AN OPPOSITEDIRECTION, DRIVE MEANS FOR MOVING SAID WIRES AT A PREDETERMINED SPEEDSUFFICIENT TO DESCHARGE THE LIQUIDS IN THE STOCK BY CENTRIFUGAL FORCETHROUGH ONE OF SAID WIRES AS SAID SANDWICHED WIRES AND STOCK PASS AROUNDSAID FIRST TURNING ROLL AND THEN THROUGH THE OTHER OF SAID WIRES AS SAIDSANDWICHED WIRES AND STOCK PASS AROUND SAID SECOND TURNING ROLL TOREMOVE SUBSTANTIALLY ALL OF THE LIQUIDS FROM THE STOCK BY CENTRIFUGALFORCE TO PRODUCE A SHEET OF PAPER OR THE LIKE, AND MEANS FOR SEPARATINGSAID FORMING WIRES AND REMOVING THE NEWLY FORMED SHEET THEREFROM.